Fuse combination with replaceable fuse element



June 27, 1950 F A, GRETSCHEL 2,512,932

FUSE COMBINATION WITH REPLACEABLE FUSE ELEMENT Filed 001;. 20, 1947 j JNVENTOR.

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M 7 www@ .irme/ffy Patented June 27, 1950 UNITED'S'TATES PATENT OFFICE FUSE COMBINATIN WITH REPLACEABLE FUSE ELEMENT Frederick A. Greischerilos Angeles, Calif. l Application October 20, 1947, Serial No. 780,791

y Claims. 1 The present invention relates to improvements in fuse plugs such as Ycommonly used in electric light circuits.

It is the general object of .my invention to provide a fuse plugwhich is tted with a replaceable fuse element. Itis a further object to provide a fuse plug combination designed for insertion and removal from a conventional type of socket and the partsv of which may be separated after removal from the socket forreplacement of a burned-out fuse element. A

With these and other objectsin view,.the invention resides in the combination hereinafter described in detail and drawings are hereto appended in which a preferred form of the invention is illustrated. M

In the drawings: Fig. 1 is a side elevationalview showing the general outline of vthe structure of the invention; Fig. 2 is a cross-sectional view taken on line 2-2 of Fig. 1 in the direction of the arrows;

Fig. 3 is a cross-sectional View through the i center of Fig. 1 and at right angles to Fig. 2; Fig. 4 is a plan view of the device of Fig. 1; Fig. 5 is a plan view of the lower portion of Fig. 1 as it appears when removed from the upper portion thereof;

Fig. 6 is a bottom view of a portion of Fig. 1; and f Fig. '7 is a detail view showing .a preferred form of replaceable fuse element.

I'he structure of the invention in the form illustrated in the drawings comprises generally a plug section I into which is seated a cap section 2. The plug section I is recessed substantially as indicated at 3 and the upper portion of this recess is enlarged to form a shoulder portion- 4 within which the cap 2 is seatable.

The plug section I is fitted at the bottom thereof with a conventional contact stud 5 and a threaded contact band 6 encompasses the intermediate portion of the plug in the usual commercially well known manner.

A contact strip 'I is suitably secured to the stud 5 and it extends upward therefrom along the inner wall of the recess 3 terminating at the top in a lip 8 which is bent at right angles to the main. portion of the strip and takes the position at the bottom of the enlarged recessed portion 4.

A second contact strip 9 extends upwardly 2 Iiange. I 5 which seats. on the top of the plug section in continued alignment with a cylindrical outer surface thereof. A cylindrical shoulder portion I 6 extends downward from a flange I5 and it is made snugly `to iit within the outer recess 4 of the plug section but does not quite reach to the bottom thereof. Diametrically opposed notches I'I are provided in the cylindrical surface of the portion *I6 at the lower end thereof andthese notches are shaped to receive the fusible element of the device; The latter is, in Fig. 7, shown to include a narrow strip I8 from which rise lips I9 and the latter are shaped to fit into the notches I'I when theelement is placed in position on the cap substantially as indicated in Fig. 3. In this position it is noticed that the strip I8 comes to rest against the bottom surface of the portion I6 and that the lips I9 do not project beyond the cylindrical surface of the part I6 but may even be placeda'slight distance within this surface. l y Thecap 2 is seatable within the plug section I in the following manner. Diametrically aligned sockets 20 are sunk into the cylindrical surface of thecup portion I6 and pins 2I are driven into these recesses to form studs outwardly projecting a short distance. As best shown in Fig. 5, recesses 22 are sunk into the cylindrical inner wall of the plug section in alignment with the projecting `ends Vof thestuds 2l and it is important to note that .annular grooves 23 extend from the bottom of these notches in opposite direction along the inner cylindrical wall of the plug section within which the studs 2l are caused to lodge when the cap is manually rotated relative to the plug section. It is also important to note that the length of these annularrecesses iS calculated to bring the fuse element I8 into alignment with the curved portions of the lips 8, I0 of the contact strips. When brought into engagement with the lips -of vthe contact strips in this manner, it is found that the 4latter become slightly depressed within the notches II thereby assuring a perfect contact between the element and these lips.

, When the thin flange I5 of the cap 2 is shaped not to extend beyond the cylindrical surface of the plug section, it is seen that the assembled plug may be screwed into its socket and removed therefrom without disturbing the relation of the .cap to the plug section. It is furthermore seen that thev cap section may be rotated on the plug section, after the plug has been removed from its The cap 2 comprises arelatvely thin annular i socket, to bring the studs into alignment with the notches 22 whereupon the cap may be withdrawn from the plug section to remove a blown fuse and inserting a replacement fuse. In order to facilitate seating and removal of the cap from the plug section, it may be found convenient to mount a pair of finger grips 25 on the upper surface of the cap. c.

The cap ispreferably made from transparent material in order that the fuse element may als 

